Not a sequel to the original Fantastic Voyage (a 1966 movie novelization), which Asimov chooses to ignore completely; the upshot isn't too much more than a sclerotically talky retread. In the 21st century, the superpowers coexist peacefully—so why do the Russians choose to kidnap frustrated brain researcher Albert Morrison (no one believes his advanced theories)? Well, genius scientist Shapirov, the inventor of miniaturization, lies in a coma, the victim of an experimental accident; the Russians need Morrison's expertise in order to tap the thoughts of the dying Shapirov (he was on the point of a dramatic breakthrough). The problem is that Morrison doesn't believe in miniaturization and, indeed, is terrified at the prospect. Still, after some judicious blackmail, he agrees to enter a specially-built submarine, along with its stereotyped crew, hearty Dezhnev, manipulative Boranova, Finno-Russian Kaliinin, and obsessive Konev: they will be shrunk to molecular size and injected into Shapirov's comatose brain. After various adventures—unsurprising stuff to fans of the first Voyage—they reemerge, the mission apparently a failure and Shapirov dead, with a mildly surprising twist ending still to come. Like much of Asimov's recent output: a novel-sized conversation, scientifically more credible than FVI but just as tepid plot-and-drama-wise. It slips down easily enough but leaves no lingering impression.